PM Lee, in his first walkabout in Punggol East since by-elections were announced, said voters need to bear this in mind when they go to polls.

"Ultimately, choose the person who can serve you well in Punggol East and also broadly in Singapore," he said to reporters after a short 15-minute walkabout around Rivervale Plaza.

There are currently eight opposition voices in Parliament -- Png Eng Huat, the MP from Hougang as well as five from Aljunied GRC (Low Thia Kiang, Sylvia Lim, Chen Show Mao, Pritam Singh and Muhamad Faisal Manap .

Gerald Giam and Yee Jenn Jong are Non-constituency members of parliament, and do not have full voting rights.

PM Lee meets residents during a short morning walkabout in Rivervale Plaza.

"But I told him his first priority is to fight and win in PE, win the support and trust of residents," said PM Lee, who was accompanied by Acting Minister for Social and Family Development Chan Chun Sing and other party members.

"When he is ready, and when I judge he is ready... I will be appointing him to a suitable political office but we will decide what, later on."

Dr Koh did not accompany him for the walkabout as he was meeting residents elsewhere in the area, but both met earlier in the morning during a breakfast meeting at the PAP Punggol East education centre.

PM Lee also assured residents that the upgrading works at the much-troubled Rivervale Plaza, which has beset by construction delays after the main contractor went bust, will be done by the middle of the year.